[article Doc Title 1a
[quickbook 1.5]
[id doc-title]
]

[/ A repeat of doc-title1, but with an explicit id. ]

[heading a1]

[include doc-title1-inc1.quickbook]

[heading a2]

[include doc-title1-inc2.quickbook]

[heading a3]

[include doc-title1-inc3.quickbook]

[heading a4]